That elves have pointy ears is one of those things everyone knows, and Peter Jackson has probably helped spread the meme further (there's an interesting discussion here about how and whether Tolkien himself intended his elves' ears to be pointed); but where does the idea originate? Certainly you can see examples in the work of Arthur Rackham and Cicely Mary Barker - but what about earlier artists? And is it purely an artistic convention, or does it have literary corroboration?
Would the players have been gluing points to their ears for the first performance of A Midsummer Night's Dream?